High T4, low range FT3: Got results back today... - Thyroid UK

Thyroid UK
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High T4, low range FT3


Got results back today from my private test and would like to know if I should be worried about my T4 levels.

TSH .02 0.55 - 4.78

FT4 1.72 0.89 - 1.76

T4 15.9 4.5 - 10.9

FT3 2.7 2.3 - 4.2

I had the same tests done in March and my FT3 was in mid range and my T4 was at upper range if I remember right. I would have to find my printout. Am just kind of wondering what might be going on. I still feel okay but not like I did in March.

16 Replies


What are you medicating now ?

Have you checked your ferritin, folate, B12 etc... You need these tone optimal to aid conversion and maximise uptake.

Meant to say iron too!


And vitamin d levels need checking too


guysgrams What medication are you on?

You have a high in range FT4 but a low in range FT3 suggesting poor conversion, but from a quick look at your previous posts you are on T3 as well as Levo.

And as Waveylines and SlowDragon have mentioned, vitamins and minerals all need to be optimal for any thyroid hormone to work properly.

Two possible:

1. Conversion issues.but your free t3 is in range. You should check your reverse t3

2. Your thyroid gland may be back to function. Do you have any overdosage symtoms from your medication. Do you have another healthy conditions?how is your life?

I am currently on Synthroid .137mcg and Lthothyronine .5 mcg twice daily. I take a number of supplements all suggested here at HealthUnlocked and have actually been feeling pretty good(selenium, B-12 methyl, vitamin B complex, Vitamin C, Zinc, Omega 3 and CoQ10. I had my Vitamin D checked again but nothing else and it was 67.4 30.0-100.0. That result changed from 61.2 from May 10th results. I had tests taken back in October 2015 because of issues and my numbers were:

TSH .0525 .350-5.50

FT4 1.42 .89-1.76

T4 12.9 4.5-10.9

FT3 2.6 2.3-4.2

That's when the Endo put me on the Lithothyronine .5mcg twice daily. Lab in March 2016:

TSH .011 .45-4.5

FT4 1.67 .82-1.77

FT3 3.9 2.0-4.4

I certainly do not want to go back to the way I was feeling previously (Fall/Winter 2014-2015). I had almost all symptoms of hypo back along with some new allergic reactions (new to me) that I am still trying to fix. I do not feel hyper in any sense but have noticed I am experiencing 'sweaty feet' again which is something I experienced just before the rug was pulled out from under me in late 2014. My results for 7/2015 were:

TSH 2.293 .35-5.50

FT4 1.31 .89-1.76

T4 11.8 4.5-10.9

FT3 2.6 2.3-4.2

Vitamin D 36.6 30.0-100.0

T3RU 27.7 24.0-35.0

Calcium 9.4 8.3-10.6

Vitamin B12 666 211-911

Ferritin 139 10-120

Folate 37.06 >5.38

Iron 79 55-170

Iron saturation 24 20-50

Iron binding capacity 336 250-450

Magnesium 2.3 1.3-2.8

Potassium 4.3 3.7-5.3

Guess I'll have to go back and have some more testing done and look at my antibodies again. They had come done to 461 in October 2015. Can anyone decipher any more info from these results? I appreciate all the help.

guysgrams in reply to guysgrams

I should say that I also take mk7 with the Vitamin D.

You are probably pushing your body too hard with that high T4 level. On the other hand, your FT3 is way low, in fact it's underrange when I look at the 2.77-5.27 range my lab uses. That FT3 should be at least mid-range, i.e. at least around 4.0 pg/ml. I suspect you would feel better if you backed off some on the T4, let your TSH rise, and added in T3 (or changed to NDT). Obviously your T4->T3 conversion isn't working well; have you been taking a trace mineral supplement, esp. for selenium?

guysgrams in reply to Eddie83

Yes, just replied. I have been taking Synthroid since I was originally diagnosed back in 1996. Have stayed on a dose of .125 mcg until last Summer when it was increased to .137 mcg and then when my FT3 didn't really move up and stayed in the low range Endo added the Lithothyronine .5 mcg twice daily. So taking the T4 back should help some?

Eddie83 in reply to guysgrams

Can't really tell without a history of rT3 tests, what is going on. But it seems obvious that the extra T4 isn't helping FT3, and your TSH is quite low, so in the absence of test data, I would lower T4. I would either drop it back to 125mcg, or use Abbott's estimate of 1.7mcg/kg body weight for T4-only full replacement. For comparison: I weigh about 78kg, and use T3=15mcg plus T4=75mcg (or 62mcg if I feel a little hyper) daily.

Unfortunately there has not been much in the way of testing anything other than the TSH and normal annual lab work by my PCP. It was only after discovering this site and feeling so poorly that I took it upon myself to do some private testing. Neither my PCP nor my Endo has taken the initiative to test RT3. I will fall back to the 6 days full dose 7th day half dose and test again in 6 weeks or so and see where that leaves me I guess.

Hey there! I was hoping you could update where you are with labs and symptoms? I ask because your numbers look just like my own!

I just posted and my FT4 is high, Rev T3 still high and now my FT3 is at the bottom of the range. Need to get rid of the Rev T3. Started to gain weight, feel cold a lot of the time, hands hurt, eye lids droop, fall asleep nightly as soon as I sit down and can sleep the night away.

have they altered your meds then? more t3?

I had been on .125 mcg synthroid only for over 20 years and then I was put on .137 mcg synthroid only and after about 6 months numbers still weren't good so T3 was added at that time. Over the course of the last year my synthroid dose has changed and is now at 112 mcg but the T3 is and has always been at 5mcg x2 daily since it was added to the regime.

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